REFERENCE VALUES OF INDICATORS OF CAPNOGRAPHY WITH NATURAL BREATHING THROUGH THE NOSE

Abstract

In 221 apparently healthy volunteers (140 men and 81 women) with the natural breathing through the nose the capnography parameters were identified: the concentration of CO₂ in the end tidal portion of the exhaled air (FetCO₂); breathing frequency (BF); structure of the respiratory cycle as the ratio of expiration time to the total time of the respiratory cycle (Rco₂), respiratory rate variability, the coefficient of variation (CV) of Rco₂ (CVRco₂). It was found out that in young males of 20-29 years old FetCO₂ was higher than in older people (5.1±0.3 and 4.9±0.4%, respectively, p=0.002) and higher than that for women of the same age (FetCO₂ was 4.7±0.4% on average, p<0.001). There were no gender differences in the people after 30 years old. Reference intervals of the capnography parameters for men aged 20-29 years old (n=100) were calculated: FetCO₂ (4.3-5.8%); BF (7.7-19.8 breaths per minute); Rco₂ (0.52-0.76); CVRco₂ (5.3-12.8%). In men and women after 30 years old (n=95), the following reference values were revealed: FetCO₂ (4.1-5.8%); BF (8.5-21.2 breaths per minute); Rco₂ (0.5-0.8); CVRco₂ (5.3-12.9%). Conclusion: gender and age are important at identification of the breathing pattern and pulmonary gas exchange reference values.